CNC machined tool forces grease in and around the hard to reach areas of the bolt roller to insure optimal performance and dependability. Easy to use, simply fill the cupped end with rifle grease and push onto the roller for complete lubrication. Durable polymer construction resists most solvents. SPECS: Polymer, black matte. 1” (2.5cm) long x 5?8' (1.6cm) dia.